Not much is known about this boss. --EDITED--
He spawns during the Wild Life Raid in the Oramond Factory and teleports himself every 10 seconds around there. He drops Glooth Glider Crank which is needed for the Glooth Glider Mount.
About the spawn:
By voting at the Magistrate NPC you can manage to make the Wild Life Raid (or the other two) active. So once per hour (starting at SS) the Raid starts. The Tremor Worm spawns random, not every time. But if he is there, he will be there for the whole day (even the Raid is over). The only way to "get rid of him" is killing him. Then he will be gone.every time while the Wild Life Raid is active.